Dry shaving apparatus with shear plate biasing means

ABSTRACT

A dry shaving apparatus having a plurality of concentric cutter guards and associated cutters, each guard being axially movable and pivotable in a resilient manner relative to the adjacent guards via a spherical outer surface, with spring means to provide a resilient force.

United States Patent 191 Tietjens et al.

[4 1 Oct. 21, 1975 DRY SHAVING APPARATUS WITH SHEAR PLATE BIASING MEANS [75] Inventors: Eduard Willem Tietjens; Dirk Jan Van Hemmen, both of Drachten, Netherlands [73] Assignee: U.S. Philips Corporation, New

York, NY.

[22] Filed: Mar. 11, 1974 [21] Appl. N0.: 449,846

[30] Foreign Application Priority Data Mar. 31, 1973 Netherlands 7304527 [52] U.S. Cl. 30/43.6 [51] Int. Cl. B26B 19/14 [58] Field of Search 30/434, 43.5, 43.6

[56] References Cited UNITED STATES PATENTS 3,694,915 10/1972 Beusink 30/435 3,715,803 2/1973 Tyler 30/435 Primary Examiner-Al Lawrence Smith Assistant ExaminerGary L. Smith Attorney, Agent, or FirmFrank R, Trifari [57] 7 ABSTRACT A dry shaving apparatus having a plurality of concentric cutter guards and associated cutters, each guard being axially movable and pivotable in a resilient manner relative to the adjacent guards via a spherical outer surface, with spring means to provide a resilient force.

13 Claims, 10 Drawing Figures U.S. Patent 011.21, 1975 Sheet 1015 3,913,225

US. Patent Oct. 21, 1975 Sheet 2 of5 3,913,225

US; Patent Oct. 21, 1975 Sheet 3 of5 3,913,225

U.S. Patent Oct.21, 1975 Sheet4 of5 3,913,225

as 87 a2 a1 77 Sheet 5 0f 5 BIASING MEANS BACKGROUND OF THE INVENTION The invention relates to a dry shaving apparatus comprising at least one round cutter guard provided with hair entrance apertures and a rotatable cutting member which co-operates with and is pressed against the cutter guard, which is disposed in a round cutter guard mount in a cutter guard holder, relative to which the cutter guard is pivotable, at least to a limited extent. Apart from the load exerted on it by the pressure forces via the cutting member, the cutter guard being subjected to an additional axial load by resiliently loading means, which press the cutter guard against the rim of the mount.

Such a dry shaving apparatus is known from the U.S. Pat. No. 3,624,681; which apparatus has four concentric guards, which are hereinafter referred to as the first, second, third and fourth cutter guard in order of decreasing diameter. I

The first cutter guard is rigidly mounted in the shaving head of the apparatus. The second cutter guard is axially depressable relative to the fixed first cutter guard. The inside of the first cutter guard serves as a cutter guard holder for the second cutter guard and is provided with a round mount. Similarly, the inside of the second cutter guard serves as a cutter guard holder with round mount for the third cutter guard, which in its turn serves the same purpose for the fourth guard. Each of the depressable cutter guards is provided with a small flange at its circumference, the diameter of said flange being greater than the mount associated with the relevant cutter guard.

The four concentric cutter guards co-operate with four equally concentric cutting members, which are adapted to be rotated simultaneously by means of a single central drive shaft. With the aid of springs disposed around the drive shaft, the cutting members are each pressed against the side of the associatedcutter guard which faces the inside of the shaving apparatus, so as to ensure a constant engagement of the cutting member with its cutter guard, which is essential for a satisfactory shaving action.

For obvious reasons the movablecutter guards can only be depressed to a limited extent when pressed against the users face, the degree of depression being determined by a stop which is attached to the cutter guard holder and situated opposite the associated mount. If the cutter guard is not depressed excessively, it is pivotable to a limited extent, thus enabling its position to be adapted to the shape of the face.

If the cutter guards were loaded only in the direction of their mounts by the springs which press the cutting members against the guards, this would generally speaking not prevent the movable cutter guards from being pressed against their stops because, as tests have revealed, the force exerted on each of the cutter guards by the users face during normal use of a shaving apparatus of the present type, is substantially greater than the force which presses the cutting member against the shear plate. Said last force should not exceed a certain comparatively low maximum value, in view of the permissible frictional losses and the development of heat between the cutting member and the cutter guard, and also in view of wear of these two components.

In the known dry shaving apparatus the movable cutter guards, apart from the previously discussed load which is exerted on them via the cutting member, are therefore additionally loaded in the direction of their mounts by resilient means especially provided for this purpose. As this load does not interfere with the engagement pressure of the cutting members against the cutter guards, it may be selected as high as is permissible in view of the specific adaptive tilting action of the movable guards.

In the drive shaft a pressure pin is mounted which is axially movable and which rotates along with said shaft, which pin is pressed against the central fourth cutter guard by a comparatively powerful spring, of which one end presses against the drive shaft and the other end against the pressure pin. At the end which faces towards the cutter guard the pressure pin is provided with a spherical bearing surface, on which the fourth cutter guard is pivoted.

The fourth guard which is thus centrally loaded trasmits the additional load via the rim of its mount to the cutter guard holder and thus to the third cutter guard which in its turn transmits it to the second cutter guard.

An additional advantage is that no extra provisions are required to prevent a cutter guard from rotating along with the cutting member. This is prevented by the friction between the cutter guard and the cutter guard holder and/or by the friction between the cutter guard and the users face.

Although this yields an improvement relative to shaving apparatus in which the cutter guards are not subjected to an additional axial load, the disadvantage remains that a cutter guard can be tilted only if there is a clearance between the cutter guard and its cutter guard holder. Not only does this result in a clearance between the cutter guard and the rim of its mount in which hairs may become entrapped, but it also demands a more intricate coupling between the cutting member and the drive shaft. Said coupling should now be capable of taking up axial as well as radial displacements of the cutting member.

SUMMARY OF THE INVENTION It is an object of the invention to provide a shaving apparatus of the type mentioned in the preamble, which while maintaining the previously mentioned advantages, does not have the described drawbacks; the invention is characterized in that the cutter guard cooperates with the rim of said! mount via a spherical outer surface, which forms part of the surface of a sphere, whose centre is disposed substantially on the axis of rotation of the cutting member.

In the shaving apparatus according to the invention the additional axial load is selected so that during normal use of the shaving apparatus no clearance exists between a cutter guard and the rim of its associated mount. They always remain in. contact. Not only does this prevent hair from penetrating a clearance between cutter guard and mount, but it also yields the substantial advantage that annoying, rattling noises are avoided. These noises always occur with shaving apparatus in which the components of the shaving head are not in constant engagement with each other.

One embodiment of the invention is characterized in that the center of the sphere is disposed at the side of the cutter guard mount which faces the interior of the shaving apparatus, and that resilient means are provided for the additional axial load of the cutter guard, the additional load bearing on the annular lower rim of the cutter guard which faces the interior of the shaving apparatus and acting as a movable supporting means for the cutter guard. Thus, the cutter guard can be supported in a simple manner, requiring a single component only.

A further embodiment is characterized in that the center of the sphere is situated at the side of the cutter guard mount which faces away from the shaving apparatus, and that the resilient loading means for the additional axial load of the cutter guard are provided in the cutter guard holder at the side which faces away from the centre of the sphere. A feature of this embodiment of the invention is that the additional axial load acts in the same direction as the load to which the cutter guard is subjected by the users skin against which the shaving apparatus is pressed during use. As a result, the resilient means need only be proportioned for exerting a small force, which slightly exceeds the force which is exerted by the cutting member on the cutter guard, but which acts an opposite direction. However, steps must be taken in order to prevent the cutter guards from being readily pulled off the apparatus.

This embodiment may be characterized further in that the resilient loading means comprises an annular magnet, which is disposed at the side of the cutter guard holder which faces the interior of the shaving apparatus and which is concentric relative to the cutter guard. v

A further characteristic may be that the cutter guard is provided with additional means in order to prevent the cutter guard from dropping out of the cutter guard holder, which means comprise a spring with multiple bends in a flat plane, which spring is clamped in the cutter guard parts of the spring extending beyond the circumference of the cutter guard.

A further embodiment of the invention is characterized in that the center of the sphere is disposed at the side of the cutter guard which faces the interior of the shaving apparatus, and that resilient means for the additional axial load of the cutter guard bears on a first bearing member which forms part of a pivotal bearing for the cutter guard. The cutter guard is pivotable relative to the first bearing member about an axis which passes substantially through the said center of the sphere, and the additional axial load is transmitted to the cutter guard via a second bearing member. This enables pivoting, with the additional axial load always acting through the center of the sphere and consequently not contributing to the tilting forces which act on the cutter guard, whatever the position of the cutter guard. The springs can be given an optimum shape so as to minimize the effect of material and production tolerances on the spring force, because they need not at the same time function as supporting members for the cutter guards.

A subsequent embodiment is characterized in that the first bearing member of the pivotal bearing is provided with a bearing mount, that the pivotable bearing comprises a second bearing member which is disposed between the cutter guard and the first bearing member, and that the second bearing member at its side which faces away from the cutter guard co-operates with the bearing mount via a surface which forms part of the surface of s sphere whose center is substantially disposed on the axis of rotation of the cutting member and which is disposed at the cutter guard side of the bearing mount. The advantage of said embodiment is in particular that only a minimum of components are required and further that slight dimensional errors of the components owing to production tolerances do not at all affect the correct operation-of the assembly.

Still another, preferred, embodiment of the invention is characterized in that the center of the sphere of the spherical outer surface is disposed at the side of the cutter guard holder which faces the interior of the shaving apparatus, that the cutter guard holder consists of a separate component which is movable relative to the housing of the shaving apparatus, that resilient means for the additional axial load of the cutter guard bear on the cutter guard holder and via said holder the additional axial load is transmitted to the cutter guard, and that between the cutter guard and the housing of the shaving apparatus a pivotal bearing is provided for the cutter guard, the axial load of the cutter guard being transmitted to the housing via the pivotal bearing. This embodiment requires only a very low pressure force between the cutter guards and the cutter guard holder, since it exclusively serves to compensate for the axial pressure forces which are exerted on the cutters and to' prevent rattling as a result of play between the cutter guards and the rims of their mounts.

Preferably, use is made of yet another characteristic of the invention, according to which the cutter guard is supported by a substantially plate-shaped supporting member in the form of a regular quadrangle, half of the quadrangle being disposed at one side of one of the diagonals in a plane which encloses an obtuse angle with the plane in which the half at the other side of the said diagonal is disposed.

Still another embodiment is characterized in that the cutter guard is cup-shaped having a substantially cylindrical raised edge, at its free end is provided with an outward flanged part; a ring is disposed around the cylindrical wall, the outer surface of which forms part of the surface of a sphere, whose center is substantially disposed on the axis of rotation of the cutting member and which cooperates with the rim of the associated mount in the cutter guard holder. The advantage of this is that cutter guards of the conventional cylindrical shape may be employed.

The invention will now be described with reference to the drawings as follows:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional elevation view of a part of a dry shaving apparatus according to the invention,

provided with three cutter guards with spherical outer surfaces, in which the cutter guards are each directly pressed against the rim of the associated cutter guard mount by a specially shaped spring,

FIG. 2 is a top plan view of a part of the shaving apparatus of FIG. 1, in which one of the cutter guards with its associated cutter has been removed,

FIG. 3 is a similar cross-section as in FIG. 1 of an embodiment in which helical springs are employed for pressing the cutter guards in position,

FIG. 4 shows a part adapted for use in conjunction with the embodiment of FIG. 3,

FIG. 5 is a partial elevation view in section of an embodiment in which during use the cutter guard is pressed more firmly against the rim of the cutter guard mount by the skin of the user,

FIG. 6 is a bottom view of the construction of FIG.

FIG. 7 is a partial elevation view in section of an embodiment in which the load on the cutter guard is transmitted via a movable pivotable bearing,

FIG. 8 is a view similar to that of FIG. 7, of another embodiment,

FIG. 9 is a view similar to FIG. 7 of another embodiment in which the load of the cutter guard is exerted via a movable cutter guard holder, and

FIG. 10 is a top plan view of a bearing part of the pivotal bearing employed in the embodiments of FIGS. 7 and 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT three cutter guards 2, two of which are visible in the Figure. The cutter guards have a number of hair entrance apertures 3 in the form of shaving slits or perforations. The cutter guards 2 each co-operate with a rotatable cutting member 4 which comprises six cutters 5. The guards as shown, when the shaver is upright, each have a lower part open at the bottom, and an upper part with said perforations in the top thereof, the guard being generally hat-shaped. The plastic housing 6 accommodates an electric motor, not shown, for driving the cutters. At the end of its rotor shaft the electric motor is provided with a pinion 7, which cooperates with three gear wheels 8. To each of the gear wheels 8. To each of the gear wheels 8, a drive stud 9 is attached, which at its top carries a drive pin 10. The drive stud 9 projects through the bottom 11 of a hair chamber 12, in which the hairs cut off by the cutters 5 are collected. In order to ensure a hair-tight passage of the drive stud 9 through the bottom 11 of the hair chamber 12, the drive stud 9 is provided with a bearing which comprises a bearing bushing 13 and a felt pad 15, which is pressed in position by a pressure plate 14.

Each of the cutter guards 2 is disposed in a round cutter guard mount 16 in the cutter guard holder 17. The cutter guards are pivotable to a limited extent relative to the cutter guard holder.

By means of a pressure spring, not shown, which is located inside the hollow drive stud 9, the cutter 4 is urged against the cutter guard 2 via the drive pin 10. Said pressure force is imparted to the rim 18 of the cutter guard mount 16 via the cutter guard 2 and thus to the cutter guard holder 17. Apart from this load by the pressure forces exerted on the cutter guard 2 via the cutting member 4, the cutter guard is subjected to an additional axial load by the spring 19. Furthermore, the cutter guard 2 co-operates with the rim 18 of the cutter guard mount 16 via a surface 20 at its outside, which forms part of the surface of a sphere, whose centre B is disposed on the axis of rotation of the drive stud 9 and thus of the cutter 4.

A supporting plate 21 is secured to the underside of the cutter guard holder 17 by a screw 22. The drive studs 9 project through openings 23 in the supporting plate 21, which openings have a diameter which is substantially smaller than the diameter of the cutter guard mount 16. The springs 19 are clamped between the cutter guards 2 and the supporting plate 21.

As can be seen in FIG. 2, the spring 19 forms a substantially plate-shaped supporting member for the cut- In the embodiment shown in FIGS. 1 and 2 the cutter A guard holder 17, in which cutter guards 2, cutters 4, springs 19 and the supporting plate 21 are disposed can bodily be swung open relative to the housing 6 of the shaving apparatus. For this purpose a resilient hinge 24 is provided at one side of the cutter guard holder. In the hinged-out position of the outer guard holder, the cutters 4 are no longer pressed against their associated cutter guard 2 by the spring in the hollow drive stud 9 and are thus disposed loosely in the cutter guard. However, the resilient supporting members 19 in this situation ensure that the cutters 4 cannot drop out of the cutter guards. For this it is necessary to select the width of the four sides of the spring 19 to be greater or at least locally greater than that of the lower edge 25 of the cutter guard 2. The resilient supporting members 19 thus have a triple function: they press the spherical outer surface 20 of the cutter guards 2 against the edges 18 of their associated mount 16, they constitute a supporting member which allows for the cutter guards 2 to be tilted to all sides, and they serve to prevent the cutters 4 from dropping out of the cutter guards 2. Nevertheless, the springs 19 are of a very simple shape can can be manufactured at a low cost price, while occupying little space.

In the embodiment of FIG. 3 the cutter guards 2 are pressed against the cutter guard holder 17 by slightly conical helical springs 26. The lower ends of the springs bear on the hook-shaped bent tabs 27 of a supporting plate 28 and their top ends against a ring 29. Said ring, as can be seen more clearly in FIG. 4, is provided with four tabs 30. Two tabs 31, which are bent out of the ring 29 in a direction which is substantially opposed to that of the tabs 30, engage with two recesses 32 at the inside of the cutter guard 2 to locate the ring 29 relative to the cutter guard. The tabs v30 as well as the tabs 27, prevent a lateral movement of the spring 26. The ring 29 comprises a more centrally disposed annular part 33, which via strips 34 is connected to the remaining part of the ring. The opening 35 of the part 33 has a greater diameter than that of the drive pin 10, thus preventing the cutters 4 from dropping out of the cutter guards 2.

A number of further embodiments of the invention will now be discussed with reference to the FIGS. 5 to 10. FIG. 5 shows a cutter guard 36 whose sphere centre B is located at the side of the cutter guard mount 37 which faces away from the interior of the shaving apparatus. In the cutter guard holder 38 an annular magnet 39 is disposed at the side of the cutter guard holder which faces towards the interior of the shaving apparatus. The magnet 39 is enclosed by a supporting plate 40, which has an opening 41 of greater diameter than the drive pin that can be inserted through said opening.

The magnet 39 pulls the steel cutter guard 36 against the rim 42 of the mount 37. Moreover, the steel cutter 43, see FIG. 6, is also magnetically pulled against the cutter guard 36. The force with which the cutter guard 36 is pulled against the rim 42 of the mount 37 by the magnet 39 need only be very small, because the pressure exerted on the cutter guard 36 by the users skin during use of the shaving apparatus, is directed towards the interior of the shaving apparatus and will consequently load the cutter guard in the direction of the rim 42 of the mount 37.

As an additional security to prevent the cutter guard 36 from dropping out of the cutter guard holder 38, spring means 44 have been provided (see FIG. 6), with a multiplicity of bends in a flat plane and which is clamped in the cutter guard 36, the parts 45 through 49 of the spring 44 extending beyond the circumference of the cutter guard 36. The parts 45 and 46 are therefore inserted through local openings 50 and 51 of the cutter guard. The parts 47, 48 and 49, however, rest on the lower edge 52 of the cutter guard. The spring 44 can be readily fitted and removed, by moving the'parts 48 and 49 towards and thus moving the parts 46 and 45 out of their associated openings 50 and 51. Apart from preventing the cutter guard 36 from dropping out of the cutter guard holder 38, the spring 44 also serves to prevent the cutter 43 from inadvertently dropping out of the cutter guard 36 when the cutter guard holder is open. The cutter 43 is pressed against the cutter guard 36 by magnetic forces, but as previously stated, said forces are comparatively small.

With respect to the embodiment shown in FIGS. and 6 the following is to be noted. The centre B of the sphere is located relatively close to the top 52 of the cutter guard 36. During use the top 52 is moved frictionally over the skin to be shaved, so that frictional forces are exerted on the top surface 52 which are substantially parallel to the said surface. The sphere centre B, is located at a relatively small distance from the top surface 52. As a result, friction torques of comparatively small magnitude are exerted on the cutter guard 36. Consequently, the cutter guard 36 will exhibit only a slight tendency to tilt as a result of the movements of the cutter guard 36 over the skin during use. Since in practice said torques cannot overcome the frictional forces occurring between the cutter guards 36 and the rim 42 of the mount 37, this means that the position of the cutter guard is exclusively determined by the forces acting on the cutter guard in an axial direction. Thus, the cutter guard 36 will always assume a position which corresponds to the local shape of the face, which position will not be affected by the to-and-fro movement of the shaving apparatus over the skin.

In the embodiment of FIG. 7 two springs 53, which are fitted in recesses 54 of the housing 6 of the shaving apparatus, via a supporting plate 55 press on a bearing member 56 for the pivotal bearing of the cutter guard 57. Via the bearing member the pressure force provided by the spring 53 is imparted to the cutter guard 57, because the supporting plate is movable relative to the housing 6 of the shaving apparatus. The sphere centre B of the cutter guard 57 is disposed at the side 58 of the cutter guard which faces towards the interior.

The shape of the bearing member 56 can be seen more clearly in FIG. 10, namely a plate-shaped supporting member in the form of a'regular quadrangle, the half of the quadrangle disposed at one side of one of the diagonals being located in a plane which encloses an obtuse angle with the plane in which the half of the other side of the said diagonal is disposed. The corner points 59, 60, 61 and 62 of the bearing member 56 are bent to a certain radius. The centres of the radii of the corners 59 and 60 are located on a straight line, which perpendicularly intersects the straight line connecting the centres of the radii of the corners 61 and 62. The dimensions of the bearing member 56 have been adapted to the dimensions of the cutter guard 57 in such a way that in the assembled condition as shown in FIG. 7, the two said lines intersect each other at the location of the sphere centre B of the cutter guard 57, thus ensuring excellent omnidirectional pivoting of the cutter guard 57. Near the corner points 61 and 62 of the bearing member 56 slightly projecting portions 63 and 64 are provided. These serve for the hingable attachment of the bearing member 56 to the supporting plate 55. The supporting plate 55 has local depressions 65 and 66 with which the projecting portions 63 and 64 engage. After fitting the projecting portions 63 and 64 in the depressions 65 and 66, the supporting plate is slightly deformed at the location of points 67 and 68 with the aid of a deformation tool, after which the bearing member 56 is hingeably attached to the supporting plate 55.

FIG. 8 shows an embodiment which on several points bears a resemblance to the embodiment of FIG. 7, so that a number of corresponding parts have corresponding reference numerals. In said embodiment a pivotal bearing is employed which comprises a first bearing member in the form of a supporting plate 69 and a second bearing member 70. The supporting plate 69 is provided with a bearing mount 71. The second bearing member 70 is disposed between the supporting plate 69 at the one side and the underside 58 of the cutter guard 57 at the other side, so that in this embodiment the pressure force of the springs 53 is also imparted to the cutter guard 57 via the supporting plate and a second bearing member. At the side 72 which faces away from the cutter guard 57 the bearing member 70 cooperates with the bearing mount 71 via a surface 73 which forms part of the surface of a sphere whose center B is substantially disposed on the axis of rotation of the cutting member (not shown) which co-operates with the cutter guard 57, i.e. at the side of the bearing mount 71 which faces towards the cutter guard 57. The sphere center B of said spherical surface coincides with the sphere center B of the spherical outer surface 74 of the cutter guard 57. The bearing member 70 has a flanged part 75 which engages with the spout-shaped part 76. By giving the spout-shaped part 76 an internal diameter which is only slightly greater than the diameter which is necessary for the passage of a drive pin for driving the cutter, the flange 75 prevents the cutter from dropping out of the cutter guard 57 when the cutter guard holder is hinged open.

The embodiment of FIG. 9 also bears a certain resemblance to that of FIG. 7, so that again corresponding parts are denoted by corresponding reference numetals. in this embodiment the cutter guard 7'7 itself does not cooperate with the rim 78 of the mount 79 in the cutter guard holder 80. Around the cylindrical outer circumference of the cup-shaped cutter guard 77 a ring 81 is provided, whose spherical outer surface 82 presses against the cutter guard holder 80. The sphere center B, however, is located in the same point as in FIG. 7. The cutter guard holder consists of a separate component which is movable relative to the housing 6 of the shaving apparatus. The resilient means for the additional axial load of the cutter guard 77 are constituted by springs 83, one of which is shown in the Figure. This is a tension spring, which at its end which is not shown in the drawing is attached to the housing 6 and at its other end 84 cooperates with a projection 85 of the cutter guard holder 80. The supporting plate 86 is rigidly attached to the housing 6 and again carries a supporting member 56 of the shape shown in FIG. 10. At the outside of the cutter guard holder 80 a capshaped part 87 is located which is attached to the housing 6 of the shaving apparatus, and which may be adjustable in height.

What is claimed is:

1. In a dry shaver including a housing, at least one cutter guard and a cooperating cutter that is rotatable about its axis, a holder in which said guard is movably mounted, the first spring means for resiliently urging said cutter axially upward (when said shaver is upright) into engagement with said guard which is thereby urged upward in engagement with said mount, the improvement in combination therewith wherein said holder includes a circular aperture defined by a rim having first diameter, said guard has an outer surface which is spherically curved, has diameter corresponding to said first diameter, and is situated within and engaging said rim, said spherical surface having its center situated substantially on said cutter axis, said guard and cutter together being both pivotable in said rim and depressible axially downward against said first spring means.

2. A shaver according to claim 1 wherein said cutter guard has a hat shape with an upper part perforated at the top thereof, and a lower part with an open bottom which faces said cutter, and wherein said center B of said spherical surface is situated in said mount below said lower part of the guard.

3. A shaver according to claim 2 further comprising second spring means which is carried by said housing and urges said guard upward in engagement with said mount, independent of said first spring means urging said cutter upward.

4. Apparatus according to claim 1 further comprising an annular shaped magnet means situated in said mount generally outward of and below said cutter guard, said guard being urged downward by magnetic force of said magnet to remain engaged to said mount.

5. Apparatus according to claim 1 further comprising holding means carried by said guard for preventing said guard from moving axially upward and out of engagement with said mount.

6. Apparatus according to claim 5 wherein said holding means comprises a spring engaged to said guard and extending generally radially outward of said spherical surface.

7. Apparatus according to claim 1 further comprising a first bearing member spring-mounted on said housing and supporting said guard.

8. Apparatus according to claim 7 further comprising a second bearing member having a lower part pivotally mounted on said first bearing member and an upper part supporting said guard.

9. Apparatus according to claim 8 wherein said second bearing member is pivotal on said first bearing member about a first axis, and said guard is pivotal on said second bearing member about a second axis generally normal to the first axis.

10; Apparatus according to claim 8 wherein said first bearing member includes an inside spherical surface and said second bearing members lower part engages said inside spherical surface the center of which 3' coincides with the center B of said spherical surface of said guard.

11. Apparatus according to claim 1 wherein said holder is axially movable relative to said housing, said holder being urged resiliently upward by force from contact with said guard, said apparatus further comprising spring means mountedon said housing and resiliently urging said holder downward.

12. Apparatus according to claim 9 wherein said first hearing member is a four-sided element bent along a diagonal, with two diagonally opposite corners defining said second pivot axis.

13. Apparatus according to claim 11 wherein said holder is an annular ring the bore of which defines said rim engaging said spherical surface of said guard.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3913225 DATED October 21, 1975 lN\/ ENTOR( I EDUARD WILLEM 'IIE'I'JENS ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[SEAL] Column 5,

line 31, delete "To each of the gear wheels 8."

Signed and Scaled this Fourth Day Of January 1977 line 32,

A ttes t:

C. MARSHALL DANN Commissioner oj'Parents and Trademarks RUTH C. MASON Arresting Officer Notice of Adverse Decision in Interference In Interference No. 99,560, involving Patent No. 3,913 and D. J. Van Hemman, DRY SHAVIN G APPARATUS WITH SHEAR PLATE BIASING MEANS, final judgment adverse to the patentees was rendered June 5, 1979, as to claims 1, 2, 5 and 7.

[Ofiicial Gazette July 22,1980.]

Disclaimer 3,913,225.-Eduard WI Tiezjens and Dirk Jan V an Hemmen, Drachten, Netherlands. DRY SHAVING APPARATUS WITH SHEAR PLATE BI- ASING MEANS. Patent dated Oct. 21, I975. Dis

, by the assignee, U.S. Philzps Corp. Hereby enters this disclaimer to claims 1, 2, 5 and 7 of said patent.

[Ofizcial Gazette July 14, 1981.] 

1. In a dry shaver including a housing, at least one cutter guard and a cooperating cutter that is rotatable about its axis, a holder in which said guard is movably mounted, the first spring means for resiliently urging said cutter axially upward (when said shaver is upright) into engagement with said guard which is thereby urged upward in engagement with said mount, the improvement in combination therewith wherein said holder includes a circular aperture defined by a rim having first diameter, said guard has an outer surface which is spherically curved, has diameter corresponding to said first diameter, and is situated within and engaging said rim, said spherical surface having its center situated substantially on said cutter axis, said guard and cutter together being both pivotable in said rim and depressible axially downward against said first spring means.
 2. A shaver according to claim 1 wherein said cutter guard has a hat shape with an upper part perforated at the top thereof, and a lower part with an open bottom which faces said cutter, and wherein said center B of said spherical surface is situated in said mount below said lower part of the guard.
 3. A shaver according to claim 2 further comprising second spring means which is carried by said housing and urges said guard upward in engagement with said mount, independent of said first spring means urging said cutter upward.
 4. Apparatus according to claim 1 further comprising an annular shaped magnet means situated in said mount generally outward of and below said cutter guard, said guard being urged downward by magnetic force of said magnet to remain engaged to said mount.
 5. Apparatus according to claim 1 further comprising holding means carried by said guard for preventing said guard from moving axially upward and out of engagement with said mount.
 6. Apparatus according to claim 5 wherein said holding means comprises a spring engaged to said guard and extending generally radially outward of said spherical surface.
 7. Apparatus according to claim 1 further comprising a first bearing member spring-mounted on said housing and supporting said guard.
 8. Apparatus according to claim 7 further comprising a second bearing member having a lower part pivotally mounted on said first bearing member and an upper part supporting said guard.
 9. Apparatus according to claim 8 wherein said second bearing member is pivotal on said first bearing member about a first axis, and said guard is pivotal on said second bearing member about a second axis generally normal to the first axis.
 10. Apparatus according to claim 8 wherein said first bearing member includes an inside spherical surface and said second bearing member''s lower part engages said inside spherical surface the center of which B'' coincides with the center B of said spherical surface of said guard.
 11. Apparatus according to claim 1 wherein said holder is axially movable relative to said housing, said hOlder being urged resiliently upward by force from contact with said guard, said apparatus further comprising spring means mounted on said housing and resiliently urging said holder downward.
 12. Apparatus according to claim 9 wherein said first bearing member is a four-sided element bent along a diagonal, with two diagonally opposite corners defining said second pivot axis.
 13. Apparatus according to claim 11 wherein said holder is an annular ring the bore of which defines said rim engaging said spherical surface of said guard. 